package com.cryptooj.project.utils;

import org.apache.http.protocol.HTTP;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;

/**
 *  网络工具类
 * */
public class NetUtils {

    /**
     *  获取请求方客户端的 IP
     *  （公式化写法）
     * */
    public static String getIpAddress(HttpServletRequest request){
        String ip = request.getHeader("x-forwarded-for");
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
            if(ip.equals("127.0.0.1")){ // 若请求来自于本机
                // 根据网卡获取本机配置的IP
                InetAddress inet = null;
                try {
                    inet = InetAddress.getLocalHost();
                } catch (Exception e) {
                    e.printStackTrace();
                }
                if(inet != null){
                    ip = inet.getHostAddress();
                }
            }
        }
        // 多个代理的情况，直接取第一个作为客户端的真实IP
        if(ip != null && ip.length() > 15){
            if(ip.indexOf(",") > 0){
                ip = ip.substring(0, ip.indexOf(","));
            }
        }
        if(ip == null){
            ip = "127.0.0.1";
        }
        return ip;
    }
}
